Hitherto, various kinds of developing agent penetrants have been investigated for increasing the coloring property of color photographic light-sensitive materials and, in particular, a process of quickening color development by adding benzyl alcohol to a color developer has been widely used at present for the processing of color photographic materials because of accelerating a coloring effect, particularly color photographic papers.
However, in the case of using benzyl alcohol, diethylene glycol, triethylene glycol, etc., must be used as the solvent therefor due to the low water solubility thereof. Since, however, the above-described compounds including benzyl alcohol have high BOD (biochemical oxygen demand) and COD (chemical oxygen demand) pollution loading values, it is preferred to avoid use of benzyl alcohol as much as possible.
Furthermore, even in the case of using the aforesaid solvent, it requires a long time to dissolve benzyl alcohol, and hence it is also better to avoid use of benzyl alcohol for the purpose of reducing the work load involved in preparing the solution of benzyl alcohol.
Also, when benzyl alcohol existing in a color developer is carried in a bleach bath or a blix (bleach-fix) bath which is a post-bath of the color developer, it causes the formation of the leuco dye of a cyan dye, which further causes the reduction of coloring density. Still further, when such benzyl alcohol exists in a bleaching solution or a blix solution, it delays the washing out speed of developer components from color photographic materials, and hence it sometimes results in adverse influences on the stability or storability of color images of processed color photographic materials. Accordingly, it is also preferred to avoid use of benzyl alcohol for these reasons also.
Color development is generally performed for about 3 to 4 minutes, but recently with the shortening of the time for delivering finished photographic products and the reduction of laboratory work, it has been desired to shorten the processing time for photographic materials.
On the other hand, when the development time for color photographic materials is shortened without using benzyl alcohol, which is a coloring accelerator, the coloring density is inevitably greatly reduced.
For solving the above-described problems, various color development accelerators have been described, for example, in U.S. Pat. Nos. 2,950,970, 2,515,147, 2,496,903, 2,304,925, 4,038,075, 4,119,462, British Patents Nos. 1,430,998, 1,455,413, Japanese Patent Application (OPI) Nos. 15831/78, 62450/80, 62451/80, 62452/80, 62453/80, 50536/83 and 162256/85 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"), Japanese Patent Publication Nos. 12422/76, 49728/80, etc. However, even by the use of these color development accelerators, a satisfactory coloring density has not yet been obtained.
Also, methods for incorporating color developing agents in color photographic materials are proposed as described, for example, in U.S. Pat. Nos. 3,719,492, 3,342,559, 3,342,597, Japanese Patent Application (OPI) Nos. 6235/81, 16133/81, 97531/82, 83565/82, etc., but these methods have disadvantages in that the color development is delayed and the formation of fog is increased, and thus are not proper methods.
Furthermore, a method of using a silver chloride emulsion as described, for example, in Japanese Patent Application (OPI) Nos. 95345/83, 232342/84, 19140/85, etc., may shorten the color development time but is not a proper method since the formation of fog is increased.
As described above, a method of obtaining color images having satisfactory quality in a shortened time using a color developer containing substantially no benzyl alcohol has not yet been found.
On the other hand, techniques of adding a compound represented by formula (I) shown hereinafter to a developing solution are disclosed in Japanese Patent Application (OPI) Nos. 106244/81 and 3532/79, etc. However, the former relates to the technique for obtaining high contrast by black-and-white development for lithography using the compound together with a 3-pyrazolidone in a black-and-white developing solution. The latter relates to the technique for increasing stability of a color developing solution by means of the addition of alkanolamines thereto. There is not disclosure regarding accelerating effect on color development at all. Therefore, benzyl alcohol could not be eliminated from the color developing solution used in color development processing in a short period of time as described in the present invention. Accordingly, when the proposals described above are employed under the condition of shortening a color development time using a color developer substantially free from benzyl alcohol, the coloring property of, in particular, magenta dye, is reduced, and a satisfactory result has not been obtained.
Further, the compound represented by formula (I) causes the formation of severe fog when used in conventional color developing solutions. However, it exhibits the excellent development accelerating effect in the case wherein benzyl alcohol is not present in the color developing solution and the developing time is short as the present invention.